Michael Domin, Kimberly-Clark:
Emerging Infectious Diseases Threaten 21st Century Global
Village
Infectious diseases are evolving to resist antibiotics at an ever-faster rate, and the days when a single antibiotic could kill a wide range of bacteria have gone. Cocktails of AB's are required and even these are becoming less effective. Vancomycin is now widely regarded as the last uniformly effective treatment for Staph. Aureus and the Centre for Disease Control is urging its use as a "drug of last resort" to delay the emergence of vancomycin resistant bacteria. With nosocomial infection being the third ranking killer in the USA after HIV and TB, the case for prevention (improved hygiene in hospitals) over cure (more antibiotic use) was now obvious.Nosocomial infections were transmitted from person to person by direct or indirect contact, and 60% of them were traceable to poor hand-washing procedures. Nonwoven wipes with or without antimicrobials, for use on hands and surfaces that come into contact with hands could therefore become a major contributor to hospital hygiene.
In response to questions:
The simplest antimicrobials i.e. chlorine and iodine were the best. The more complex the molecule, the easier it became for an organism to incorporate it into it's biology and develop resistance.
Standard dishwashing fluid had proved to be the best handwash detergent in hospitals.
Vancomycin is indeed the last antibiotic of the current series. Drug companies abandoned AB R&D as paybacks fell. Work has now restarted but a vancomycin replacement is unlikely to be on the market before vancomycin resistant organisms have evolved. Vancomycin use must therefore be restricted.
Disposable diapers used in hospitals are not regarded as hazardous waste, at least in California.
Infectious diseases are evolving to resist antibiotics at an ever-faster rate, and the days when a single antibiotic could kill a wide range of bacteria have gone. Cocktails of AB's are required and even these are becoming less effective. Vancomycin is now widely regarded as the last uniformly effective treatment for Staph. Aureus and the Centre for Disease Control is urging its use as a "drug of last resort" to delay the emergence of vancomycin resistant bacteria. With nosocomial infection being the third ranking killer in the USA after HIV and TB, the case for prevention (improved hygiene in hospitals) over cure (more antibiotic use) was now obvious.Nosocomial infections were transmitted from person to person by direct or indirect contact, and 60% of them were traceable to poor hand-washing procedures. Nonwoven wipes with or without antimicrobials, for use on hands and surfaces that come into contact with hands could therefore become a major contributor to hospital hygiene.
In response to questions:
The simplest antimicrobials i.e. chlorine and iodine were the best. The more complex the molecule, the easier it became for an organism to incorporate it into it's biology and develop resistance.
Standard dishwashing fluid had proved to be the best handwash detergent in hospitals.
Vancomycin is indeed the last antibiotic of the current series. Drug companies abandoned AB R&D as paybacks fell. Work has now restarted but a vancomycin replacement is unlikely to be on the market before vancomycin resistant organisms have evolved. Vancomycin use must therefore be restricted.
Disposable diapers used in hospitals are not regarded as hazardous waste, at least in California.
Blake Kuster, Absorbent Technologies Inc: Global
Production Of Superabsorbents Recently announced expansions of SAP
production will take world capacity to 1.35 million tonnes by 2001, this being
equally split between North America, Europe and Asia. The expansion is being
driven by both supply and demand factors: a cheap and readily available supply
of acrylic acid, and growing demand from the disposables industry. Acrylic acid
feedstock, propylene, is expected to remain in the 10-13 c/lb range until 2001,
and of the 1200 million tonnes of acrylic acid produced in the USA, over 30% is
now routinely converted into the glacial form from which SAP's are made. SAP
makers are therefore experiencing attractive raw material pricing and are
encouraged to sell aggressively.
Stockhausen is the market leader with 22% of capacity, followed by Nippon Shokubai (18%), Chemdal (12%), BASF (12%), Dow Chemical (11%), Sanyo Chemical (7%) and Sumitomo Seika (7%). 81% of SAP's are used in diapers and training pants, 13% in adult incontinence and 2% in femcare. The US and Japanese markets are felt to be saturated, but Europe and the rest of the world - especially Asia - have growth potential. Within the market sectors, adult incontinence has the greatest growth potential. Diapers are already more absorbent than necessary, so it is clear that factors other than performance, i.e. the aesthetic and storage advantages of ultra-thin products, will drive the predicted SAP content up from 50 to 60%
Other trends of interest:
The development of less absorbent but more permeable SAP's (higher cross-linking).
The development of products specially for air-laid cores, the rapid (25% per year)
Growth of the new bladder control pads.
The emergence of diaper backsheet fracture problems arising from the high SAP loadings.
In response to questions:He put the world market for superabsorbent fibres at 2000 tonnes/year currently but felt these were selling largely into packaging end-uses. They would gain a foothold in disposables and would grow from there.
SAP-loaded air-laid's would be used to "cut and place" absorbency strategically in diapers. This would not translate into more SAP usage.
New polymers can be expected. (After all acrylic acid products are not biodegradable and consumerism can be expected to lead to a tax on waste.)
CMC based superabsorbents are far too expensive to challenge acrylics.
SAP still has to prove itself to US meat packers before food contact uses will grow. However Japan and Australia have already accepted it in food packaging.
Henning Skov-Jensen, M&J Fibertech: The Prospects For An Air-Lay Super-Site
He defined a super-site as a single plant air-laying 100,000 tonnes per year and festooning the output to feed on-site diaper production. The plant would have an on-line calender to densify the output to 0.4 gms/cc and bond it. It could even be built at a pulp-mill to achieve further integration.
The paper, like the earlier version given at Inda-Tec in September, was notable for it's comprehensive breakdown of the manufacturing costs of the super-site revealing the M&J machine would cost $58M. 6000 tonnes of short-cut bico. reinforcing fibre would be needed at an assumed price of $2/kg. The pulp would cost 55c/kg and the superabsorbent (45,000 tonnes/year) would cost $2/kg.
John Starr and Pricie Hanna (Consultants): Value Chain Analysis
The principles of "Value Chain" and Michael Porter's "5 Forces" analytical methods were applied to the disposables industry. The conclusions from such analyses were driving pulp companies to move downstream to capture more of the value in a disposable diaper by supplying air-laid pulps ready-mixed with SAP's. This would save the converter the trouble of having to defibrate and lay pulp/SAP on every diaper machine and would allow cheaper, more consistent products to be manufactured. The pulp supplier would extract greater value from the chain.
Large-scale investment was already taking place to provide air-laid pre-formed cores to the diaper and sanitary towel makers, and the pulp producers were in the vanguard. These cores would combine the functions of acquisition, distribution and retention in a multilayer stucture.
Other technology trends emerging from the analysis:Softer, loftier, microdenier topsheets, either spun laid or carded.
Stretchable covers and breathable fabric backsheets
Odour absorbing, pH neutralising SAP's
Andrew Urban (Consultant): The Troubled Private Label Diaper Industry in the USA.
Most retailers now sell branded diapers at a loss in order to attract mothers into their stores. Why do the retailers still want private label diapers on the shelves and how can the private label producers profitably make comparable diapers to sell at even lower prices? With the leading US private label producer - Paragon Trade Brands - now bankrupt thanks to P&G and Kimberly Clark patent infringement law-suits, answers to the latter question were not obvious. However retailers continue to want them because they are profitable, and because they help them to persuade the brand suppliers to keep prices down.
Market trends mentioned were as follows:
Private label diaper share fell from 20.1% in July 98 to 18.6% in July 99.
However annual shares for 98-99 were the same as for 97-98.
"Pampers"/"Huggies" share ratio fell from 28.4/31.3 to 26.3/34.6 over the last 13 week period.
"Luvs" share is essentially unchanged within the 15-15.5% range over the last year.
Private label costs will increase due to royalty payments.
Conclusion: The private label business is sick, but not dying. It will survive as long as retailers need it's diapers on the shelves.
Dick Moran (Consultant): Diaper Design Changes
The most important innovations in diaper design following P&G's kick-start of the industry with the original Z-fold one-piece diaper in 1970 were listed as:
J&J's introduction of tapes to replace pins
P&G's use of the hour-glass shape and elastic legs on "Luvs" in 1975
P&G's use of thin superabsorbent cores and compressed packs in 1985
P&G and K-C's simultaneous use of elasticated interior barrier cuffs in 1991
The introduction of Pull-Up's training pants by K-C
The extension of the pant design to baby diapers by Unicharm.
The need for perfect containment of urine and faeces has driven developments to date, but baby-care is now emerging as the new focus. Drypers use of aloe in lotion diapers did well in 1998 and this year P&G's "Rash Guard" is making inroads at the incredible price of 37.9 c/diaper (compared with private label Kroger "Ultra Comforts" by Paragon at 19.3 c/diaper.) "Rash Guard" claims are related to the use of a proprietary lotion on the coverstock, the use of a treated inner cuff, a breathable cover and a super-dry core.
In Japan Unicharm's "Moony Delicate Care" features an apertured hydroentangled top-sheet to achieve a more textile-like appearance.
Looking to the future, Dick (ex P&G) saw the following as "winners":
P&G's "Uni-Futur" diaper now on sale in SE Asia using a 4" wide elastic waist with "ears" and a thin rectangular core looking just like a pre-formed core ought to look. (This was a low-cost product being made available in just 3 sizes to cover the normal 5-size range.)
Unicharm's "Moony Man" pull-up diaper with ingenious elastication of the crotch to form the leg-bands.
Kimberly-Clark's expansion of the training pant range with an overnighter suitable for 85lb+ "infants".
And of course, the P&G "Rash Guard" principle.
Chris Barcomb, National Starch & Chemical Co: The Industrial Hygiene Of Chemically Bonded Nonwovens Unlike natural rubbers and latexes, the new synthetic emulsions do not contain proteins that could cause skin irritation and allergic reactions. Emulsion polymers have a long history of safe use in FDA regulated areas. Furthermore the latest Dur-o-set® Elite series of ethyl vinyl acetate binders contains only a tenth of the vinyl acetate monomer and formaldehyde residues found in conventional EVA's.
The latest self-crosslinking binders can give nonwovens yielding only 15ppm formaldehyde, sufficiently close to the "background" level of 3-5 ppm found on cellulose to be of no health or toxicological concern. Nevertheless, research striving for zero formaldehyde binders continues.
Edward Powers, Celanese Acetate: Low Temperature Calendar Bonding With Cellulose Acetate
Cellulose diacetate melts with some decomposition at 235oC and is generally regarded as a difficult prospect in thermal bonding. However if the moisture content is raised, the water acts as a fugitive plasticiser under pressure and webs can be calendered at around 170oC to give respectable nonwoven strength. 100% acetate, 80/20 rayon/acetate and 60/40 rayon/acetate blends were studied at a range of moisture contents, bonding temperatures and pressures using both plain and patterned calenders.
The best moisture content appears to be around 100%, but even 20% makes a difference. In patterned-roll calendering, 60% water, 157oC bonding temperature at 400 pli roll pressure gave good results. At 175oC the strengths declined due to the film-like nature of the bond points.
Dr Klaus Kohlhammer, Wacker Polymer Systems: Dry Emulsion Binders for Air-Laid Nonwovens.
Spray-bonding of air-laid pulp nonwovens or waddings gives good surface strength and integrity but fails to penetrate the thicker products and results in easily delaminated fabrics. The new Vinnex® emulsion copolymers in dry powder form can be air-laid along with the pulp and disperse uniformly through the thickness.of the web. When webs containing them are steamed or moisturised with 10 to 30% water, the binder becomes sticky and soft, adhering well to any surrounding polar fibres. Curing at temperatures above 150oC crosslinks the polymer and renders the final nonwoven heat and water resistant.
The current binders are especially suitable for thick waddings based on natural fibres and find application in powder bonded fibre sheets used in automotive industry.
Calvin Woodings (Consultant): Advanced Cellulosic Nonwovens.
The nonwoven industry was founded on the ready availability of low-cost viscose rayon fibres, and this fibre continued as the leading raw material until the mid-seventies. Since then the reducing cost of synthetics coupled with their easy conversion into binder-free spun-laid and melt-blown fabrics caused a steady decline in rayon's market share. Ways of redressing the cost disadvantage of man-made cellulosics over the coming decades involved operating the new solvent spun cellulose process (lyocell) on scales comparable to modern polyester fibre plants and changing it's feedstock from costly dissolving pulps to something more like bleached Kraft.
The market justification for a major investment in man-made cellulosics arose from the predicted inability of cotton to expand acreage or yield in line with predicted demand over the next half century. One study predicted the need for an additional 70 million tonnes of fibre by 2050 (a 150% increase) and while most of this would still originate from fossil fuels, natural cellulose was seen as the most economical and environmentally secure future source of "comfort fibres".
Past and future developments in spun-laid and "melt-blown" cellulosics were illustrated by reference to the patent literature. Recent work by Weyerhauser had demonstrated that on a small scale at least, excellent lyocell fibres could be spun from an NMMO solution of a treated Kraft pulp. Furthermore, direct extrusion of such solutions onto a conveyor belt could be set-up to give spun-laid cellulosic nonwovens, "melt-blown" microfibres nonwovens or a crimped tow free from the damage inherent in mechanical crimping processes. Centrifugal spinning was also described.
Kaj Back, Ahlstrom Lystil: A 3-Layer Soft Wet-Wipe.
This Finnish wet-laid nonwoven producer has developed a way of making a bulky three-layer wipe to compete with the thin, but cheap, creped paper now used in most single-pack wet wipes. The process uses one headbox and achieves true integration of the layers - typically a thick pulp/bico core with thin rayon/bico skin - to give a soft surface. Other combinations are of course possible, but competing in the single pack wet-wipe market requires low cost materials. Single-packs are used for refreshing wipes, spectacle cleaners, computer wipes, shoe cleaners and cosmetic samplers. The packaging machines for these are incapable of using hydroentangled fabrics, but cope well with the Trinitex® product which offers improved liquid retention, bulk and softness over creped paper.
Although more expensive than creped paper, is Trinitex® is a minor component of the total cost of single-packs and the extra cost is easily recouped from savings in lotion consumption. Furthermore, the extra thickness and absorbency means that significantly less fabric is needed per pack.
Rosario Maggio, ICBT Perfojet: The New "Spunjet" Spunbond Process.
ICBT Perfojet has seen an opportunity to supply PP spunbond lines based on designing out the known deficiencies of existing lines and building to a higher quality standard. They claim:
Improved aerodynamics in the quench zone
Better quench-air temperature and flow control (0.2oC and 0.02 m/s accuracy)
Modular concept (identical 500mm spinning modules across the machine width)
Better polymer distribution and melt temperature uniformity (+/- 0.5oC) to the spinning beam arising from multiple distribution plates
Crosswise draw force variations reduced to +/- 2-3%
Improved control system with friendly man-machine interface
Easy maintenance arising from modularity, quick disconnect techniques, and easy access
Integrated ducting, cabling and piping included in cost.
The new machine is said to run faster, and make finer fabrics with less waste and downtime than the competition. Filament speeds of 2500 to 3000 metres/minute were claimed and while the current pilot line works at 120 kg.hour/metre, it is being modified to achieve 220 kh/m at 1.4 denier per fil.
Jim Hanson, MTS: A Review of Airlaid Competition.
His 1998 review had predicted 3 new big air-laid installations for '99, and two have materialised: McAirlaid's 30,000 tonner and Buckeye's 50,000 tonner. The viability of airlaying for pre-forming femcare cores is now assured and its commercial use in diapers is imminent.
Key pointers to future developments were:
12mm man-made fibres were now handleable at commercial rates.
Only 5% bonding fibre is required (used to be 13%).
Thermal bonding fibres and methods are changing to alleviate the dusting problem.
Further increases in SAP loadings (up to 80%) can be expected.
The best pulps come from the dissolving mills. Mercerised pulp is especially good.
600 m/min at 5 metres width is now widely regarded as feasible.
The 100,000 tonne machine WILL be built.
Airlaying will outperform carding as a way of feeding uniform webs at high speed into hydroentanglement.
Smaller production units will make sense to supply the smaller diaper makers.
Air-laying will be used to make 100% man-made fibre acquisition layers.
Air layers would be used in cities to process waste paper (excluding newsprint).
Cotton linters were excellent in air-lay for wet-wipes. The process could be used to put a cotton veneer on a pulp core.
Another "super-site" announcement is expected in the spring.
Bruce Kirk, BT Associates: Sanitary Tissue Market Developments.
Worldwide usage of sanitary tissue is about 19.4 million tonnes per year, or about 6% of total paper and board usage. North America accounts for 35% of this, but is a mature market with less than 1.9% annual growth since 1990. By contrast, the Asian market (27% of the total) is growing at 6.8% p.a. and even Europe (26% of the total) is growing at 4.7% p.a. Capacity will expand by 5.9% in 1999 with the construction of 8 new large scale units, 4 by P&G, 2 by K-C and one each by Fort James and Georgia Pacific. World rankings have changed dramatically since 1995 due to frenetic merger and acquisition activity. K-C the current world leader and number two US producer was fifth in the US before acquiring Scott Paper. Fort James the current US leader was formed from the previous second and third place producers, Fort Howard and James River. No's 3 and 4 in the world, P&G and SCA have also grown by acquisition and the process will continue. While a long list of acquisition targets remains, the current leaders are expected to stay leaders. P&G are expected to "prove that brands will travel" by introducing "Charmin" and "Bounty" to Europe and Asia.
Dieter Muller, Bremen University: Odour Reduction In Adult Incontinence Products.
He reviewed how the sense of smell worked, highlighting the molecular forms giving rise to pleasant and unpleasant odours. The concept of "threshold concentration" was important because odour molecules did not have to be eliminated if they could be absorbed (or diluted) to concentrations below the detectable threshold. Temperature, humidity, training, cultural background and environmental factors all affected an individuals appreciation of odours. Some natural and synthetic macromolecules had porous structures that could absorb and retain odours, and in solution, these could be sprayed onto the acquisition layer of adult incontinence products. Gas chromatography had been used to check the concentration of urine odours (ammonia, ketones, dimethylsulphone etc) before and after absorption onto a nonwoven sprayed with cyclodextrin solution. 30 to 50% reductions were obtained, with higher absorbtion being possible at longer contact times.
In response to a question, he had no data on the effectiveness of baking soda as an odour reducer.
Sten Bjornberg, KBS Development: Natural V. Synthetic Blood For Testing Sanitary Napkins
Five test fluids made from human and animal bloods were compared with 4 synthetic fluids for viscosity and surface tension, for absorbtion speed and rewet (on "Always" and "Libresse" pads).
The conclusions:
Real blood is much more viscous than the synthetics at low shear rates.
Sheeps blood viscosity drops dramatically on cooling.
Synthetic body fluids absorb faster than blood, while synthetic menses absorbs more slowly.
Stockhausen fluid doesn't absorb after the first insult, but human blood continues to absorb through the second and third insults.
Pad absorbtion is increased by movement.
Rewet levels are generally higher with real blood.
Overall, real blood is the best test fluid with defibrillated sheeps blood coming a close second. (The human blood biohazard issue can be neatly avoided by always testing with your own blood!)
In response to questions:
McAirlaid cores give faster absorbtion than Walkisoft cores,
P&G's "Dri-weave" is a very superior topsheet compared with spunbond.
Milk is a better test fluid than synthetic urine but is really not good enough.
Ian Cheyne, Camelot Technologies: Unconventional Absorbent Fabrics.
The combination of high-loft and air laying techniques was shown to be capable of giving pads with good absorbency and better aesthetics than air-laid alone. Two approaches were examined. The first involved air-laying a mixture of superabsorbent fibres (30%) and pulp onto a pre-formed, through-air bonded, high-loft acquisition layer. This gave superior acquisition times and runoffs, but the resulting pad was too stiff due largely to its increased thickness. The second involved needling a carded web into a pre-formed air-laid comprising AD and absorbtion layers also using superabsorbent fibres. The resulting 3-layer web gave great aesthetics and much improved acquisition rate, rewet, and run-off. Patents targeting applications in diapers, training pants and adult incontinence have been filed.
Edward Mclean, Cotton Incorporated: The Use Of Cotton In Air-Laid Nonwovens.
Cotton linters and blends with woodpulps had been compared to woodpulps in hammermilling, air-laying and absorbency testing with the help of MTS and Buckeye Cellulose Absorbent Products Group:
Cotton requires less energy to defibrate but gives more nits.
Cotton tends to block the screens needed for pulp, but runs OK slowly without the screens.
Cotton is more absorbent than pulp (18.5 g/gm v. 17 gms/gm) but does not distribute fluid as well at normal core densities.
It gives similar retention under pressure.
It can be regarded as broadly equivalent to pulp technically.
Consumers would always express a preference for the cotton containing cores.
Cotton Incorporated spends 8% of turnover on marketing and will licence anyone who incorporates more than 60% of cotton in an absorbent core to use their new trademark Absorblend™. (SAP content is excluded from the blend ratio calculation)
They could not give a figure for the tonnage of linters currently available in America, but indicated that second-cut linters, i.e. the very short hairs normally left on the seed after linter removal, could be more available in future.
Other new developments mentioned were:
Wet-laid 60/40 linter/pulp nonwovens give dramatically better wipes.
An announcement of new cotton-containing baby wipes can be expected within 6 months.
Cotton/synthetic topsheets are being used over a cotton core to make diapers for newborns. (launched at recent Neo-Natal World Show)
Ram Shet (Consultant): Extractables in Hygiene Products.
Extractables were defined as the material leached out of SAP during 16 hours of contact with 0.9% saline solution. They comprised mainly low-molecular weight sodium polycrylate and could range from 5% of a high cross-linked SAP to 20% of a low cross-linked SAP. "Potential Extractables" arose from other materials used to make the pads, i.e. debonders, finishes, surfactants, adhesives etc.
In addition to their possible affect on delicate skin, extractables reduce absorbency under load and swelling rate and contribute to gel-blocking.
They arise from:
Monomer depletion during polymerisation.
Non-uniform or low density cross-linking.
High "hold temperature" and dwell time after reaction. (Required to reduce acrylic acid monomer residues below 1000ppm)
High drying temperatures (again required to minimise monomer residues).
Whether or not they diffuse from the wet gel depends on their molecular weight relative to the molecular weight between cross-links in the main gel network. However surface cross-linking technology had been a huge breakthrough, enabling more extractables to be retained than would otherwise be possible.
James Westphal, Troika Nonwovens Inc. And Danweb: Air-Laid Nonwoven Technology.
This year's new capacity start-ups and announcements were summarised as follows:
Air Formed Composites 6000 tpa multibond Danweb line in the USA
McAirlaid's 40,000 tpa densified core Danweb line in Germany
Concert's 17,500 tpa multibond Kroyer/M&J line in Germany (2000)
Main Spa's 10,000 tpa multibond Danweb line in Italy (2000)
BBA's ???tpa Kroyer/M&J line in China (2001)
His talk also featured :
Buckeye's "Streamliner" ad for the Vizorb® pantyliner core using cotton linters.
Buckeye's "Cottonaire" pantyliners where cotton usage obviates the need for coverstock.
Single-lane festooning by KorTec GmbH allowing converters to run for an hour on a single package. (and also 7 to 10 tonnes of airlaid core per containerload)
Multi-lane festooning from Gevas GmbH, packing 70mm wide 150 gsm webs at 0.1 g/cc and 1200mm roll diameter. (The final pack contains 10 rolls per block, or 102 kgs all spliced together for continuous running.)
Rayonier's continued interest in scaling up the Novathin™ air-laid core.
Future targets for the machine suppliers:
Lower costs per tonne output
Better control systems
Higher first quality yields (up from the current 80%)
Breaking the 500m/min barrier
Selling several 40,000 tonne machines to inco-pad producers
75% of lines on multibonding by 2003
Adopting festooning as the packaging of choice
Adding densification to production lines
Foaming colour onto products destined for the European tablewear market.
Larry Wilson, Dow Chemical: Determining The Core-Shell Structure Of SAP Particles By STXM.
The core-shell SAP's give the best performance but the shell can rupture after abrasion in diaper manufacture. This rupture allows the lower cross-linked internal polymer with its higher levels of extractables to leak out on wetting, and spoils the absorbency under load performance.
To allow the core shell structure to be clearly seen in the wet state, Dow has used high- energy synchrotron X-rays as the illumination in scanning transmission microscopy.
A thin section of granule, moistened and sealed in silicon nitride capsules are viewed. 2 to 10 micron skins, sharply defined or of graduated density depending on the manufacturing process, are clearly visible.
Ball milling was used as a severe simulation of abrasion in conversion, and a relationship between shell morphology and attrition sensitivity was found.
Dr Lindsay Kerr, National Association for Continence: Consumer Focus 99 Survey Results.
NAFC has 127,500 members, 98000 of whom were mailed the 1999 survey questionnaire. 2000 completed forms were returned by the deadline.
Analysis of results suggests: The average incontinent person is 67.2 years old.
Their average household income is $44,360.
61.3% are on Medicare, 25% enrolled in HMO's, 5.7% are covered by Medicaid and 2.4% had no health insurance at all.
19.2% of men and 8.2% of women reported no control of their bladders.
Consumer dissatisfaction with treatment measures has risen from 34.6% in '93 to 62.1% in '96 and 63.9% in '99.
5.3% of respondents had never sought professional help compared with 11% in 96 and 13.5% in '99.
About 50% of both men and women rated non-surgical, non-invasive, non-drug treatments as most helpful.
Only 3.3% felt cured by their treatment.
Only 8.6% were "very pleased" with the outcome of treatment.
With regard to disposables use, tissues were the most common absorbent for light problems, pads were used by those moderately incontinent, and the heavily incontinent used durables or catheters.
The figures were said to indicate the presence of very many unfilled needs in the marketing sense of the phrase, and very many innovation opportunities for technologists.
US incontinence care costs were put at $16.4 billion.
Ruth Zielinski, Childbirth And Womens Services: The Causes And Prevention Of Diaper Rash.
Common diaper rash arises when overhydrated skin is irritated by friction and the ammonia/high pH arising from faecal-enzyme breakdown of urine. Secondary problems can arise due to infections (candida) and allergic reactions to diaper components.
Prevention measures:
Keeping the skin dry and healthy by changing diapers as soon as they were wet (20 times a day for a new born and 6-7 times a day for a 1 year old.)
Modern superabsorbent diapers are much better than the old ones except when mothers decide to leave them on for longer.
Mild cleansing is recommended at every diaper change, but wet-wipes containing fragrances or chemicals should be avoided.
Barrier creams were helpful but only if applied sparingly. Too much could block the coverstock and hold urine against the skin.
Lotion diapers with cream applied to the coverstock in a controlled fashion were looking promising.
Breast fed babies have a lower incidence of rash than formula fed babies.
Treatments:
The low risk approach is to stop using diapers.
Ventilated diapers would be better than breathable.
Question:
When does a diaper that guards against diaper rash become a medical device?
Cliff Marshall, Bandz Inc: Savings And Benefits From Thinner Air-Laid Cores.
The view that air-laid cores will increase diaper costs is based on raw material considerations only. Bandz have attempted to calculate the additional savings from the use of air laid:
$650,000 would be saved from reductions in packaging required for the thinner diapers.
$260,000 would be saved from doubling truck payloads.
$54,000 would be saved on energy use (no hammermilling).
$45,000 would be saved from reduced downtime.
$26,000 would be saved from a 20% reduction in maintenance costs.
Another $26,000 would be saved by avoiding the 2% SAP loss that accompanies conventional diaper making.
In addition pre-formed cores would remove the defibration bottleneck on some lines and lead to increased throughputs.
Conclusion:
Compared with an additional $990,000 in annual raw material cost for each diaper line, an overall saving of at least $71,000 per annum is achievable by switching to pre-formed cores.
Ivo Edward Ruzek (Consultant): Baby Diapers: The Continuous Challenge
Recent diaper design improvements have been directed towards:
Allowing diapers to work for several urinations.
More perfect containment of urine within the core.
Dermatological skin treatments.
Considering the next generation Mr Ruzek expected the real topsheet, i.e. the hydrophilic portion between the hydrophobic leg cuffs and edge strips to get smaller. This would place great demands on the surfactants used to keep polypropylene coverstock wettable through several urinations, and would lead to the use of soft, bulky hydroentangled and apertured structures stabilised by through-air bonding. The need for permanent hydrophilicity could even let in carded hydrophilic fibres, polyester being given an example.
For the hydrophobic areas of topsheet, SMS appears ideal until the need for it to carry cosmetic lotions arises. With lotion SMS becomes transparent to varying degrees and looks awful. The solution is apparently to use transparent microdenier (around 1 dpf) spunbonds that conceal the lotion while being attractively soft and textile-like.
For the Cores, increased SAP levels to extend diaper use time and reduce thickness will demand superior acquisition and distribution layers to deal with the slower uptake of the low-woodpulp cores. These will need to be permanently hydrophilic and resilient. Bico polyesters with spiral crimp would be one solution and blends of polyesters with differing melt temperatures would be another. High SAP cores may also need a core-wrap to keep the powder in, and tissue would no longer be appropriate. Ultra-light spunbonds or SMS structures at around 10 gsm would be needed.
Backsheets would of course be porous microfibre SMS structures, leakage being controlled by fluorocarbons. They would be printed or embossed to simulate textiles.
Gary Gilkes, Datasorb: A Test-Rig And Software Package For Pad Absorbency Testing.
The Datasorb "Protester" simplifies testing, removes operator error and allows the standardisation of test parameters such as fluid flow rate, hydrostatic head pressure, and acquisition end-point. Adaptations allow it to measure absorbency under various loads and rewet.
The following papers were in a simultaneous session. The notes below are from the published summaries:
Gary Hawkins & Cathy Dorher, Eastman Chemical Co: New Polyethylene Resins For Hygienic Films
Eastman Chemical Company produces MXSTEN™ elastomers and HIFOR XTREME™LLDPE polymers for film in hygienic applications. Films fabricated from the new resins are characterized by excellent bi-directional tear strength, puncture resistance, tensile strength, elastic recovery and stiffness. Fortunately, the increased stiffness does not take away from the soft feel provided by polyethylene polymers. A better MD/TD balance of properties, when compared to conventional metallocene catalyzed polymers, is achieved, and the unique molecular architecture can promote enhanced breathability and elastic recovery.
Larry Wadsworth, Tandec: Enhanced Barrier Performance Of Bicomponent Fiber Meltblown Nonwovens
The preferred polymer for producing meltblown is polypropylene, although PE, PET, PBT, PCT and most other thermoplastics may be processed. Bicomponent fibers may also be successfully melt-blown. Although core/sheath (CS), side-by-side (S/S) and other configurations may be prepared, the S/S configuration is preferred because of the possibility that greater fiber crimp can be achieved due to density gradients on the different sides of the B/C fibers.
Kathleen Hachey & Alton Gasper, 3M Company: New Polymer Melt Additives
Two new polymer melt additive materials have been developed by 3M. Although the materials can be used with a variety of substrates, including films and fibers, their primary utilization will be in nonwovens. These products are not intended for hygiene applications but are suitable for use in sorbents and wipes for the hydrophilic polymer melt additive. The repellent melt additive is expected to have significant utility in protective garment applications. This paper presented data related to the applications mentioned above as well as information relative to melt additive functionality.
Stockhausen is the market leader with 22% of capacity, followed by Nippon Shokubai (18%), Chemdal (12%), BASF (12%), Dow Chemical (11%), Sanyo Chemical (7%) and Sumitomo Seika (7%). 81% of SAP's are used in diapers and training pants, 13% in adult incontinence and 2% in femcare. The US and Japanese markets are felt to be saturated, but Europe and the rest of the world - especially Asia - have growth potential. Within the market sectors, adult incontinence has the greatest growth potential. Diapers are already more absorbent than necessary, so it is clear that factors other than performance, i.e. the aesthetic and storage advantages of ultra-thin products, will drive the predicted SAP content up from 50 to 60%
Other trends of interest:
The development of less absorbent but more permeable SAP's (higher cross-linking).
The development of products specially for air-laid cores, the rapid (25% per year)
Growth of the new bladder control pads.
The emergence of diaper backsheet fracture problems arising from the high SAP loadings.
In response to questions:He put the world market for superabsorbent fibres at 2000 tonnes/year currently but felt these were selling largely into packaging end-uses. They would gain a foothold in disposables and would grow from there.
SAP-loaded air-laid's would be used to "cut and place" absorbency strategically in diapers. This would not translate into more SAP usage.
New polymers can be expected. (After all acrylic acid products are not biodegradable and consumerism can be expected to lead to a tax on waste.)
CMC based superabsorbents are far too expensive to challenge acrylics.
SAP still has to prove itself to US meat packers before food contact uses will grow. However Japan and Australia have already accepted it in food packaging.
Henning Skov-Jensen, M&J Fibertech: The Prospects For An Air-Lay Super-Site
He defined a super-site as a single plant air-laying 100,000 tonnes per year and festooning the output to feed on-site diaper production. The plant would have an on-line calender to densify the output to 0.4 gms/cc and bond it. It could even be built at a pulp-mill to achieve further integration.
The paper, like the earlier version given at Inda-Tec in September, was notable for it's comprehensive breakdown of the manufacturing costs of the super-site revealing the M&J machine would cost $58M. 6000 tonnes of short-cut bico. reinforcing fibre would be needed at an assumed price of $2/kg. The pulp would cost 55c/kg and the superabsorbent (45,000 tonnes/year) would cost $2/kg.
John Starr and Pricie Hanna (Consultants): Value Chain Analysis
The principles of "Value Chain" and Michael Porter's "5 Forces" analytical methods were applied to the disposables industry. The conclusions from such analyses were driving pulp companies to move downstream to capture more of the value in a disposable diaper by supplying air-laid pulps ready-mixed with SAP's. This would save the converter the trouble of having to defibrate and lay pulp/SAP on every diaper machine and would allow cheaper, more consistent products to be manufactured. The pulp supplier would extract greater value from the chain.
Large-scale investment was already taking place to provide air-laid pre-formed cores to the diaper and sanitary towel makers, and the pulp producers were in the vanguard. These cores would combine the functions of acquisition, distribution and retention in a multilayer stucture.
Other technology trends emerging from the analysis:Softer, loftier, microdenier topsheets, either spun laid or carded.
Stretchable covers and breathable fabric backsheets
Odour absorbing, pH neutralising SAP's
Andrew Urban (Consultant): The Troubled Private Label Diaper Industry in the USA.
Most retailers now sell branded diapers at a loss in order to attract mothers into their stores. Why do the retailers still want private label diapers on the shelves and how can the private label producers profitably make comparable diapers to sell at even lower prices? With the leading US private label producer - Paragon Trade Brands - now bankrupt thanks to P&G and Kimberly Clark patent infringement law-suits, answers to the latter question were not obvious. However retailers continue to want them because they are profitable, and because they help them to persuade the brand suppliers to keep prices down.
Market trends mentioned were as follows:
Private label diaper share fell from 20.1% in July 98 to 18.6% in July 99.
However annual shares for 98-99 were the same as for 97-98.
"Pampers"/"Huggies" share ratio fell from 28.4/31.3 to 26.3/34.6 over the last 13 week period.
"Luvs" share is essentially unchanged within the 15-15.5% range over the last year.
Private label costs will increase due to royalty payments.
Conclusion: The private label business is sick, but not dying. It will survive as long as retailers need it's diapers on the shelves.
Dick Moran (Consultant): Diaper Design Changes
The most important innovations in diaper design following P&G's kick-start of the industry with the original Z-fold one-piece diaper in 1970 were listed as:
J&J's introduction of tapes to replace pins
P&G's use of the hour-glass shape and elastic legs on "Luvs" in 1975
P&G's use of thin superabsorbent cores and compressed packs in 1985
P&G and K-C's simultaneous use of elasticated interior barrier cuffs in 1991
The introduction of Pull-Up's training pants by K-C
The extension of the pant design to baby diapers by Unicharm.
The need for perfect containment of urine and faeces has driven developments to date, but baby-care is now emerging as the new focus. Drypers use of aloe in lotion diapers did well in 1998 and this year P&G's "Rash Guard" is making inroads at the incredible price of 37.9 c/diaper (compared with private label Kroger "Ultra Comforts" by Paragon at 19.3 c/diaper.) "Rash Guard" claims are related to the use of a proprietary lotion on the coverstock, the use of a treated inner cuff, a breathable cover and a super-dry core.
In Japan Unicharm's "Moony Delicate Care" features an apertured hydroentangled top-sheet to achieve a more textile-like appearance.
Looking to the future, Dick (ex P&G) saw the following as "winners":
P&G's "Uni-Futur" diaper now on sale in SE Asia using a 4" wide elastic waist with "ears" and a thin rectangular core looking just like a pre-formed core ought to look. (This was a low-cost product being made available in just 3 sizes to cover the normal 5-size range.)
Unicharm's "Moony Man" pull-up diaper with ingenious elastication of the crotch to form the leg-bands.
Kimberly-Clark's expansion of the training pant range with an overnighter suitable for 85lb+ "infants".
And of course, the P&G "Rash Guard" principle.
Chris Barcomb, National Starch & Chemical Co: The Industrial Hygiene Of Chemically Bonded Nonwovens Unlike natural rubbers and latexes, the new synthetic emulsions do not contain proteins that could cause skin irritation and allergic reactions. Emulsion polymers have a long history of safe use in FDA regulated areas. Furthermore the latest Dur-o-set® Elite series of ethyl vinyl acetate binders contains only a tenth of the vinyl acetate monomer and formaldehyde residues found in conventional EVA's.
The latest self-crosslinking binders can give nonwovens yielding only 15ppm formaldehyde, sufficiently close to the "background" level of 3-5 ppm found on cellulose to be of no health or toxicological concern. Nevertheless, research striving for zero formaldehyde binders continues.
Edward Powers, Celanese Acetate: Low Temperature Calendar Bonding With Cellulose Acetate
Cellulose diacetate melts with some decomposition at 235oC and is generally regarded as a difficult prospect in thermal bonding. However if the moisture content is raised, the water acts as a fugitive plasticiser under pressure and webs can be calendered at around 170oC to give respectable nonwoven strength. 100% acetate, 80/20 rayon/acetate and 60/40 rayon/acetate blends were studied at a range of moisture contents, bonding temperatures and pressures using both plain and patterned calenders.
The best moisture content appears to be around 100%, but even 20% makes a difference. In patterned-roll calendering, 60% water, 157oC bonding temperature at 400 pli roll pressure gave good results. At 175oC the strengths declined due to the film-like nature of the bond points.
Dr Klaus Kohlhammer, Wacker Polymer Systems: Dry Emulsion Binders for Air-Laid Nonwovens.
Spray-bonding of air-laid pulp nonwovens or waddings gives good surface strength and integrity but fails to penetrate the thicker products and results in easily delaminated fabrics. The new Vinnex® emulsion copolymers in dry powder form can be air-laid along with the pulp and disperse uniformly through the thickness.of the web. When webs containing them are steamed or moisturised with 10 to 30% water, the binder becomes sticky and soft, adhering well to any surrounding polar fibres. Curing at temperatures above 150oC crosslinks the polymer and renders the final nonwoven heat and water resistant.
The current binders are especially suitable for thick waddings based on natural fibres and find application in powder bonded fibre sheets used in automotive industry.
Calvin Woodings (Consultant): Advanced Cellulosic Nonwovens.
The nonwoven industry was founded on the ready availability of low-cost viscose rayon fibres, and this fibre continued as the leading raw material until the mid-seventies. Since then the reducing cost of synthetics coupled with their easy conversion into binder-free spun-laid and melt-blown fabrics caused a steady decline in rayon's market share. Ways of redressing the cost disadvantage of man-made cellulosics over the coming decades involved operating the new solvent spun cellulose process (lyocell) on scales comparable to modern polyester fibre plants and changing it's feedstock from costly dissolving pulps to something more like bleached Kraft.
The market justification for a major investment in man-made cellulosics arose from the predicted inability of cotton to expand acreage or yield in line with predicted demand over the next half century. One study predicted the need for an additional 70 million tonnes of fibre by 2050 (a 150% increase) and while most of this would still originate from fossil fuels, natural cellulose was seen as the most economical and environmentally secure future source of "comfort fibres".
Past and future developments in spun-laid and "melt-blown" cellulosics were illustrated by reference to the patent literature. Recent work by Weyerhauser had demonstrated that on a small scale at least, excellent lyocell fibres could be spun from an NMMO solution of a treated Kraft pulp. Furthermore, direct extrusion of such solutions onto a conveyor belt could be set-up to give spun-laid cellulosic nonwovens, "melt-blown" microfibres nonwovens or a crimped tow free from the damage inherent in mechanical crimping processes. Centrifugal spinning was also described.
Kaj Back, Ahlstrom Lystil: A 3-Layer Soft Wet-Wipe.
This Finnish wet-laid nonwoven producer has developed a way of making a bulky three-layer wipe to compete with the thin, but cheap, creped paper now used in most single-pack wet wipes. The process uses one headbox and achieves true integration of the layers - typically a thick pulp/bico core with thin rayon/bico skin - to give a soft surface. Other combinations are of course possible, but competing in the single pack wet-wipe market requires low cost materials. Single-packs are used for refreshing wipes, spectacle cleaners, computer wipes, shoe cleaners and cosmetic samplers. The packaging machines for these are incapable of using hydroentangled fabrics, but cope well with the Trinitex® product which offers improved liquid retention, bulk and softness over creped paper.
Although more expensive than creped paper, is Trinitex® is a minor component of the total cost of single-packs and the extra cost is easily recouped from savings in lotion consumption. Furthermore, the extra thickness and absorbency means that significantly less fabric is needed per pack.
Rosario Maggio, ICBT Perfojet: The New "Spunjet" Spunbond Process.
ICBT Perfojet has seen an opportunity to supply PP spunbond lines based on designing out the known deficiencies of existing lines and building to a higher quality standard. They claim:
Improved aerodynamics in the quench zone
Better quench-air temperature and flow control (0.2oC and 0.02 m/s accuracy)
Modular concept (identical 500mm spinning modules across the machine width)
Better polymer distribution and melt temperature uniformity (+/- 0.5oC) to the spinning beam arising from multiple distribution plates
Crosswise draw force variations reduced to +/- 2-3%
Improved control system with friendly man-machine interface
Easy maintenance arising from modularity, quick disconnect techniques, and easy access
Integrated ducting, cabling and piping included in cost.
The new machine is said to run faster, and make finer fabrics with less waste and downtime than the competition. Filament speeds of 2500 to 3000 metres/minute were claimed and while the current pilot line works at 120 kg.hour/metre, it is being modified to achieve 220 kh/m at 1.4 denier per fil.
Jim Hanson, MTS: A Review of Airlaid Competition.
His 1998 review had predicted 3 new big air-laid installations for '99, and two have materialised: McAirlaid's 30,000 tonner and Buckeye's 50,000 tonner. The viability of airlaying for pre-forming femcare cores is now assured and its commercial use in diapers is imminent.
Key pointers to future developments were:
12mm man-made fibres were now handleable at commercial rates.
Only 5% bonding fibre is required (used to be 13%).
Thermal bonding fibres and methods are changing to alleviate the dusting problem.
Further increases in SAP loadings (up to 80%) can be expected.
The best pulps come from the dissolving mills. Mercerised pulp is especially good.
600 m/min at 5 metres width is now widely regarded as feasible.
The 100,000 tonne machine WILL be built.
Airlaying will outperform carding as a way of feeding uniform webs at high speed into hydroentanglement.
Smaller production units will make sense to supply the smaller diaper makers.
Air-laying will be used to make 100% man-made fibre acquisition layers.
Air layers would be used in cities to process waste paper (excluding newsprint).
Cotton linters were excellent in air-lay for wet-wipes. The process could be used to put a cotton veneer on a pulp core.
Another "super-site" announcement is expected in the spring.
Bruce Kirk, BT Associates: Sanitary Tissue Market Developments.
Worldwide usage of sanitary tissue is about 19.4 million tonnes per year, or about 6% of total paper and board usage. North America accounts for 35% of this, but is a mature market with less than 1.9% annual growth since 1990. By contrast, the Asian market (27% of the total) is growing at 6.8% p.a. and even Europe (26% of the total) is growing at 4.7% p.a. Capacity will expand by 5.9% in 1999 with the construction of 8 new large scale units, 4 by P&G, 2 by K-C and one each by Fort James and Georgia Pacific. World rankings have changed dramatically since 1995 due to frenetic merger and acquisition activity. K-C the current world leader and number two US producer was fifth in the US before acquiring Scott Paper. Fort James the current US leader was formed from the previous second and third place producers, Fort Howard and James River. No's 3 and 4 in the world, P&G and SCA have also grown by acquisition and the process will continue. While a long list of acquisition targets remains, the current leaders are expected to stay leaders. P&G are expected to "prove that brands will travel" by introducing "Charmin" and "Bounty" to Europe and Asia.
Dieter Muller, Bremen University: Odour Reduction In Adult Incontinence Products.
He reviewed how the sense of smell worked, highlighting the molecular forms giving rise to pleasant and unpleasant odours. The concept of "threshold concentration" was important because odour molecules did not have to be eliminated if they could be absorbed (or diluted) to concentrations below the detectable threshold. Temperature, humidity, training, cultural background and environmental factors all affected an individuals appreciation of odours. Some natural and synthetic macromolecules had porous structures that could absorb and retain odours, and in solution, these could be sprayed onto the acquisition layer of adult incontinence products. Gas chromatography had been used to check the concentration of urine odours (ammonia, ketones, dimethylsulphone etc) before and after absorption onto a nonwoven sprayed with cyclodextrin solution. 30 to 50% reductions were obtained, with higher absorbtion being possible at longer contact times.
In response to a question, he had no data on the effectiveness of baking soda as an odour reducer.
Sten Bjornberg, KBS Development: Natural V. Synthetic Blood For Testing Sanitary Napkins
Five test fluids made from human and animal bloods were compared with 4 synthetic fluids for viscosity and surface tension, for absorbtion speed and rewet (on "Always" and "Libresse" pads).
The conclusions:
Real blood is much more viscous than the synthetics at low shear rates.
Sheeps blood viscosity drops dramatically on cooling.
Synthetic body fluids absorb faster than blood, while synthetic menses absorbs more slowly.
Stockhausen fluid doesn't absorb after the first insult, but human blood continues to absorb through the second and third insults.
Pad absorbtion is increased by movement.
Rewet levels are generally higher with real blood.
Overall, real blood is the best test fluid with defibrillated sheeps blood coming a close second. (The human blood biohazard issue can be neatly avoided by always testing with your own blood!)
In response to questions:
McAirlaid cores give faster absorbtion than Walkisoft cores,
P&G's "Dri-weave" is a very superior topsheet compared with spunbond.
Milk is a better test fluid than synthetic urine but is really not good enough.
Ian Cheyne, Camelot Technologies: Unconventional Absorbent Fabrics.
The combination of high-loft and air laying techniques was shown to be capable of giving pads with good absorbency and better aesthetics than air-laid alone. Two approaches were examined. The first involved air-laying a mixture of superabsorbent fibres (30%) and pulp onto a pre-formed, through-air bonded, high-loft acquisition layer. This gave superior acquisition times and runoffs, but the resulting pad was too stiff due largely to its increased thickness. The second involved needling a carded web into a pre-formed air-laid comprising AD and absorbtion layers also using superabsorbent fibres. The resulting 3-layer web gave great aesthetics and much improved acquisition rate, rewet, and run-off. Patents targeting applications in diapers, training pants and adult incontinence have been filed.
Edward Mclean, Cotton Incorporated: The Use Of Cotton In Air-Laid Nonwovens.
Cotton linters and blends with woodpulps had been compared to woodpulps in hammermilling, air-laying and absorbency testing with the help of MTS and Buckeye Cellulose Absorbent Products Group:
Cotton requires less energy to defibrate but gives more nits.
Cotton tends to block the screens needed for pulp, but runs OK slowly without the screens.
Cotton is more absorbent than pulp (18.5 g/gm v. 17 gms/gm) but does not distribute fluid as well at normal core densities.
It gives similar retention under pressure.
It can be regarded as broadly equivalent to pulp technically.
Consumers would always express a preference for the cotton containing cores.
Cotton Incorporated spends 8% of turnover on marketing and will licence anyone who incorporates more than 60% of cotton in an absorbent core to use their new trademark Absorblend™. (SAP content is excluded from the blend ratio calculation)
They could not give a figure for the tonnage of linters currently available in America, but indicated that second-cut linters, i.e. the very short hairs normally left on the seed after linter removal, could be more available in future.
Other new developments mentioned were:
Wet-laid 60/40 linter/pulp nonwovens give dramatically better wipes.
An announcement of new cotton-containing baby wipes can be expected within 6 months.
Cotton/synthetic topsheets are being used over a cotton core to make diapers for newborns. (launched at recent Neo-Natal World Show)
Ram Shet (Consultant): Extractables in Hygiene Products.
Extractables were defined as the material leached out of SAP during 16 hours of contact with 0.9% saline solution. They comprised mainly low-molecular weight sodium polycrylate and could range from 5% of a high cross-linked SAP to 20% of a low cross-linked SAP. "Potential Extractables" arose from other materials used to make the pads, i.e. debonders, finishes, surfactants, adhesives etc.
In addition to their possible affect on delicate skin, extractables reduce absorbency under load and swelling rate and contribute to gel-blocking.
They arise from:
Monomer depletion during polymerisation.
Non-uniform or low density cross-linking.
High "hold temperature" and dwell time after reaction. (Required to reduce acrylic acid monomer residues below 1000ppm)
High drying temperatures (again required to minimise monomer residues).
Whether or not they diffuse from the wet gel depends on their molecular weight relative to the molecular weight between cross-links in the main gel network. However surface cross-linking technology had been a huge breakthrough, enabling more extractables to be retained than would otherwise be possible.
James Westphal, Troika Nonwovens Inc. And Danweb: Air-Laid Nonwoven Technology.
This year's new capacity start-ups and announcements were summarised as follows:
Air Formed Composites 6000 tpa multibond Danweb line in the USA
McAirlaid's 40,000 tpa densified core Danweb line in Germany
Concert's 17,500 tpa multibond Kroyer/M&J line in Germany (2000)
Main Spa's 10,000 tpa multibond Danweb line in Italy (2000)
BBA's ???tpa Kroyer/M&J line in China (2001)
His talk also featured :
Buckeye's "Streamliner" ad for the Vizorb® pantyliner core using cotton linters.
Buckeye's "Cottonaire" pantyliners where cotton usage obviates the need for coverstock.
Single-lane festooning by KorTec GmbH allowing converters to run for an hour on a single package. (and also 7 to 10 tonnes of airlaid core per containerload)
Multi-lane festooning from Gevas GmbH, packing 70mm wide 150 gsm webs at 0.1 g/cc and 1200mm roll diameter. (The final pack contains 10 rolls per block, or 102 kgs all spliced together for continuous running.)
Rayonier's continued interest in scaling up the Novathin™ air-laid core.
Future targets for the machine suppliers:
Lower costs per tonne output
Better control systems
Higher first quality yields (up from the current 80%)
Breaking the 500m/min barrier
Selling several 40,000 tonne machines to inco-pad producers
75% of lines on multibonding by 2003
Adopting festooning as the packaging of choice
Adding densification to production lines
Foaming colour onto products destined for the European tablewear market.
Larry Wilson, Dow Chemical: Determining The Core-Shell Structure Of SAP Particles By STXM.
The core-shell SAP's give the best performance but the shell can rupture after abrasion in diaper manufacture. This rupture allows the lower cross-linked internal polymer with its higher levels of extractables to leak out on wetting, and spoils the absorbency under load performance.
To allow the core shell structure to be clearly seen in the wet state, Dow has used high- energy synchrotron X-rays as the illumination in scanning transmission microscopy.
A thin section of granule, moistened and sealed in silicon nitride capsules are viewed. 2 to 10 micron skins, sharply defined or of graduated density depending on the manufacturing process, are clearly visible.
Ball milling was used as a severe simulation of abrasion in conversion, and a relationship between shell morphology and attrition sensitivity was found.
Dr Lindsay Kerr, National Association for Continence: Consumer Focus 99 Survey Results.
NAFC has 127,500 members, 98000 of whom were mailed the 1999 survey questionnaire. 2000 completed forms were returned by the deadline.
Analysis of results suggests: The average incontinent person is 67.2 years old.
Their average household income is $44,360.
61.3% are on Medicare, 25% enrolled in HMO's, 5.7% are covered by Medicaid and 2.4% had no health insurance at all.
19.2% of men and 8.2% of women reported no control of their bladders.
Consumer dissatisfaction with treatment measures has risen from 34.6% in '93 to 62.1% in '96 and 63.9% in '99.
5.3% of respondents had never sought professional help compared with 11% in 96 and 13.5% in '99.
About 50% of both men and women rated non-surgical, non-invasive, non-drug treatments as most helpful.
Only 3.3% felt cured by their treatment.
Only 8.6% were "very pleased" with the outcome of treatment.
With regard to disposables use, tissues were the most common absorbent for light problems, pads were used by those moderately incontinent, and the heavily incontinent used durables or catheters.
The figures were said to indicate the presence of very many unfilled needs in the marketing sense of the phrase, and very many innovation opportunities for technologists.
US incontinence care costs were put at $16.4 billion.
Ruth Zielinski, Childbirth And Womens Services: The Causes And Prevention Of Diaper Rash.
Common diaper rash arises when overhydrated skin is irritated by friction and the ammonia/high pH arising from faecal-enzyme breakdown of urine. Secondary problems can arise due to infections (candida) and allergic reactions to diaper components.
Prevention measures:
Keeping the skin dry and healthy by changing diapers as soon as they were wet (20 times a day for a new born and 6-7 times a day for a 1 year old.)
Modern superabsorbent diapers are much better than the old ones except when mothers decide to leave them on for longer.
Mild cleansing is recommended at every diaper change, but wet-wipes containing fragrances or chemicals should be avoided.
Barrier creams were helpful but only if applied sparingly. Too much could block the coverstock and hold urine against the skin.
Lotion diapers with cream applied to the coverstock in a controlled fashion were looking promising.
Breast fed babies have a lower incidence of rash than formula fed babies.
Treatments:
The low risk approach is to stop using diapers.
Ventilated diapers would be better than breathable.
Question:
When does a diaper that guards against diaper rash become a medical device?
Cliff Marshall, Bandz Inc: Savings And Benefits From Thinner Air-Laid Cores.
The view that air-laid cores will increase diaper costs is based on raw material considerations only. Bandz have attempted to calculate the additional savings from the use of air laid:
$650,000 would be saved from reductions in packaging required for the thinner diapers.
$260,000 would be saved from doubling truck payloads.
$54,000 would be saved on energy use (no hammermilling).
$45,000 would be saved from reduced downtime.
$26,000 would be saved from a 20% reduction in maintenance costs.
Another $26,000 would be saved by avoiding the 2% SAP loss that accompanies conventional diaper making.
In addition pre-formed cores would remove the defibration bottleneck on some lines and lead to increased throughputs.
Conclusion:
Compared with an additional $990,000 in annual raw material cost for each diaper line, an overall saving of at least $71,000 per annum is achievable by switching to pre-formed cores.
Ivo Edward Ruzek (Consultant): Baby Diapers: The Continuous Challenge
Recent diaper design improvements have been directed towards:
Allowing diapers to work for several urinations.
More perfect containment of urine within the core.
Dermatological skin treatments.
Considering the next generation Mr Ruzek expected the real topsheet, i.e. the hydrophilic portion between the hydrophobic leg cuffs and edge strips to get smaller. This would place great demands on the surfactants used to keep polypropylene coverstock wettable through several urinations, and would lead to the use of soft, bulky hydroentangled and apertured structures stabilised by through-air bonding. The need for permanent hydrophilicity could even let in carded hydrophilic fibres, polyester being given an example.
For the hydrophobic areas of topsheet, SMS appears ideal until the need for it to carry cosmetic lotions arises. With lotion SMS becomes transparent to varying degrees and looks awful. The solution is apparently to use transparent microdenier (around 1 dpf) spunbonds that conceal the lotion while being attractively soft and textile-like.
For the Cores, increased SAP levels to extend diaper use time and reduce thickness will demand superior acquisition and distribution layers to deal with the slower uptake of the low-woodpulp cores. These will need to be permanently hydrophilic and resilient. Bico polyesters with spiral crimp would be one solution and blends of polyesters with differing melt temperatures would be another. High SAP cores may also need a core-wrap to keep the powder in, and tissue would no longer be appropriate. Ultra-light spunbonds or SMS structures at around 10 gsm would be needed.
Backsheets would of course be porous microfibre SMS structures, leakage being controlled by fluorocarbons. They would be printed or embossed to simulate textiles.
Gary Gilkes, Datasorb: A Test-Rig And Software Package For Pad Absorbency Testing.
The Datasorb "Protester" simplifies testing, removes operator error and allows the standardisation of test parameters such as fluid flow rate, hydrostatic head pressure, and acquisition end-point. Adaptations allow it to measure absorbency under various loads and rewet.
The following papers were in a simultaneous session. The notes below are from the published summaries:
Gary Hawkins & Cathy Dorher, Eastman Chemical Co: New Polyethylene Resins For Hygienic Films
Eastman Chemical Company produces MXSTEN™ elastomers and HIFOR XTREME™LLDPE polymers for film in hygienic applications. Films fabricated from the new resins are characterized by excellent bi-directional tear strength, puncture resistance, tensile strength, elastic recovery and stiffness. Fortunately, the increased stiffness does not take away from the soft feel provided by polyethylene polymers. A better MD/TD balance of properties, when compared to conventional metallocene catalyzed polymers, is achieved, and the unique molecular architecture can promote enhanced breathability and elastic recovery.
Larry Wadsworth, Tandec: Enhanced Barrier Performance Of Bicomponent Fiber Meltblown Nonwovens
The preferred polymer for producing meltblown is polypropylene, although PE, PET, PBT, PCT and most other thermoplastics may be processed. Bicomponent fibers may also be successfully melt-blown. Although core/sheath (CS), side-by-side (S/S) and other configurations may be prepared, the S/S configuration is preferred because of the possibility that greater fiber crimp can be achieved due to density gradients on the different sides of the B/C fibers.
Kathleen Hachey & Alton Gasper, 3M Company: New Polymer Melt Additives
Two new polymer melt additive materials have been developed by 3M. Although the materials can be used with a variety of substrates, including films and fibers, their primary utilization will be in nonwovens. These products are not intended for hygiene applications but are suitable for use in sorbents and wipes for the hydrophilic polymer melt additive. The repellent melt additive is expected to have significant utility in protective garment applications. This paper presented data related to the applications mentioned above as well as information relative to melt additive functionality.
C R Woodings Nov 99
